Field of the Invention
The present invention relates to a plasma etching apparatus by which a plate-shaped workpiece can be processed.
Description of the Related Art
In electronic apparatuses represented by mobile phones and personal computers, device chips provided with electronic circuits are indispensable components. A device chip can be produced, for example, by a method wherein a front surface of a wafer formed from a semiconductor material such as silicon is partitioned into a plurality of regions by a plurality of division lines (streets), then an electronic circuit is formed in each of the regions, and the wafer is divided along the streets.
In recent years, for such purposes as reducing the device chips in size and weight, the wafers after the formation of the electronic circuits have come to be more often thinned by grinding or the like. If a wafer is thinned by grinding, however, strains due to grinding (grinding strains) would be left in the ground surface, lowering the deflective strength of the device chips. Taking this problem into account, the grinding strains are often removed by such a method as plasma etching, after the grinding of the wafer (see, for example, Japanese Patent Laid-Open No. 2000-353676).